Évaluation de la vulnérabilité à la pollution potentielle par les pesticides, de la nappe côtière alluvionnaire de la plaine de Metline-Ras Jebel-Raf Raf, Nord-Est tunisien, selon la méthode DRASTIC appliquée par les systèmes d’information géographique

L’exploitation des ressources en eau de la nappe de Metline-Ras Jebel-Raf Raf est un impératif économique jugé prioritaire étant donné que cette région est une région agricole par excellence puisqu’une grande partie de la population s’active dans le domaine agricole. L’utilisation des pesticides dans le domaine de l’agriculture ne cesse de s’accentuer, de ce fait une étude de la vulnérabilité à la pollution de la nappe par les pesticides paraissait nécessaire. L’étude de la vulnérabilité à la pollution par les pesticides de la nappe de la plaine côtière de Metline-Ras Jebel-Raf Raf a été effectuée en appliquant la méthode DRASTIC pesticides, par les logiciels des systèmes d’information géographique (SIG) : ARC/Info et Idrisi. La carte de vulnérabilité obtenue, montre des zones à vulnérabilité élevée, moyenne, et faible. Les zones à vulnérabilité élevée occupent 33 % de la superficie totale de la plaine, celles à vulnérabilité moyenne occupent 53 %, et celles à vulnérabilité faible occupent 14 %. Ces résultats montrent que la nappe étudiée est une nappe assez vulnérable à la pollution par les pesticides, de plus, les zones à vulnérabilité élevée se concentrent dans des région agricoles, là où les pesticides sont fréquemment utilisés, ce qui augmente le risque de pollution

Spondylodiscitis due to Propionibacterium acnes: report of twenty-nine cases and a review of the literature.

International audiencePropionibacterium acnes is the most frequent anaerobic pathogen found in spondylodiscitis. A documented case required microbiological proof of P. acnes with clinical and radiological confirmation of inflammation in a localized region of the spine. Microbiological samplings were obtained by surgery or aspiration under radiological control. Twelve males and 17 females (median age, 42 years) with spondylodiscitis due to P. acnes were diagnosed within the last 15 years. Three patients were immunosuppressed. All patients reported back pain as the main symptom, and most were afebrile. Three patients had a peripheral neurological deficit, one a motor deficit, and two a sensory deficit attributable to the infection; and six patients had an epidural abscess. The most frequent risk factor was surgery, which was present in the history 28 of 29 (97%) patients. The mean delay between spinal surgery and onset of disease was 34 months, with a wide range of 0-156 months. Osteosynthesis material was present in twenty-two cases (76%). In 24 (83%) patients, additional surgery, such as débridement or spondylodesis, was performed. Previous osteosynthesis material was removed in 17 of the 22 (77%) patients where it was present. Total cure was reported in all patients, except one, after a mean duration of antibiotic therapy of 10.5 weeks (range, 2-28 weeks). In conclusion, spondylodiscitis due to P. acnes is an acute infection closely related to previous surgery. The most prominent clinical feature is pain, whereas fever is rare, and the prognosis is very good

Modélisation stochastique de la sédimentation d'un réservoir dans un bassin versant semi-aride

Sedimentation in large reservoirs is a major concern in semi-arid regions characterized by severe seasonal water scarcity. As a contribution to improved sediment management, this study analyses the real case of the reservoir of Sidi Yacoub in the north of Algeria. First, a dynamic model of the reservoir was set up and used to estimate past water and sediment inflows (period 1990-2010) based on data recorded by the dam operator and measurements at a gauging station located downstream of the reservoir. Second, in a stochastic framework using the statistical characteristics of inflow and outflow discharges, a projection of future sedimentation was performed until 2030, assuming stationarity of the statistical distributions. Third, the model was used to investigate the influence of possible climate change and to quantify the positive effects of soil conservation measures upstream